Inhibition of Plant Growth by Halogenated Benzoic Acids C. W . H u f f m a n , ' E. M. G o d a r , ' a n d D. C. T o r g e s o n 2
Thirty-four substituted benzoic acid derivatives were applied to tomato and Pinto bean foliage. Among the group of trihalogen-substituted derivatives evaluated, the 2,3,5-substituted members2,3,5-triiodo (TIBA), 2-bromo-3,5-diiodo, 2-chloro3,5-diiodo, 2-iodo-3,5-dichloro, 2,3,5-tribromo, 2bromo-3,5-chloro, 2-iodo-3,5-dibromo, and 2,3,5trichloro-were more effective in inhibiting growth and more phytotoxic than derivatives substituted in other positions. In general, growth inhibition was correlated with formative, epinastic, and other abnormal morphological changes. The di- and monohalogenated derivatives were relatively in-
rganic chemicals as plant growth regulators will probably head the list of factors to increase crop yields and lower production costs for the farmer. At present, herbicides are the most important commercial plant growth regulators, but interest in plant growth retardants, inhibitors, and dwarfing chemicals is mounting. Several chemicals which inhibit the growth of grass, tobacco suckers, and flowers are now o n the market. Halogenated benzoic acids have marked effects o n plants, are growth inhibitors rather than retardants, and in a few cases are used as selective weed killers. Plant growth inhibitors may produce several beneficial effects (Cathey, 1964b). Five characteristic plant changes cited by Cathey (1964a) are: Staminate flower production is inhibited and pistillate flower formation is greatly increased in cucumber and spinach plants; treated plants are less susceptible to water stress and take u p less water than untreated ones; leaves of treated bean and petunia plants are protected from photochemical air pollutants while the ones o n untreated plants are severely damaged; frost resistance of treated herbaceous plants is increased; and resistance to high salt content and p H change in the soil is increased. Later reports claim increased yields of soybeans (Anderson, 1966, 1907), grapes (Coombe, 1965), cherries (Tukey, 1965), and apples (Stebbins, 1965) from plants treated with growth-inhibiting chemicals. Improved control of some insects (Tahori et ul., 1962) and plant diseases (Crossan and Fieldhouse, 1964) are secondary benefits. A recent development is the antilodging effect of varied plant growth inhibitors. Soybean (Army, 1966) and small grain (Beatty, 1965) producers will soon have new chemicals to help control lodging and facilitate harvesting. One plant growth regulator which reduces soybean height is 2,3,5-triiodobenzoic acid (TIBA). This chemical has intrigued plant biochemists for many years. Its major
0
active. Eight derivatives of TIBA were also evaluated, but, with the exception of the methyl ester, were considerably less active than the parent acid. The 2,3,5-halogenated derivatives were more effective also in inhibiting growth of soybeans than the other substituted acids evaluated. Abnormal morphological changes were somewhat less striking o n soybean than o n Pinto bean. TIBA reduces polar auxin transport to a greater extent than any halogenated benzoic acid tested thus far. Therefore, these related acids probably will not prove better than TIBA for inhibiting vegetative growth and increasing bean yields.
effect is an inhibition of 3-indolylacetic acid (IAA) transport from the apex of growing plants to other plant parts. TIBA was shown (Keitt and Baker, 1966) to be more effective than any of the 14 halogenated benzoic acids tested. This decrease in auxin transport causes changes in plant growth and flowering. Treatment of indeterminate soybean plants (Greer and Anderson, 1965) with TIBA a t the start of flowering caused the plants to change from vegetative to seed development more rapidly than normal. The soybean plant structure was benefited by decreasing plant height, decreasing top weight, and providing earlier ground cover through increased lower branch growth. These effects gave increased bean yields. Maximum yields were obtained when the soybeans were grown in narrow rows with high plant populations (Anderson, 1966,1967). Since TIBA reduces vegetative growth, this new soybean production system provides greater photosynthetic efficiency as measured by a n increased bean yield of about 20%. I t will make a n important contribution to the economical production of needed protein. The chlorinated benzoic acids sold as herbicides have undesirable toxic and formative effects o n beans and, therefore, are not useful for retarding growth. One compound, 3-amino-2,5-dichlorobenzoicacid (Amiben), has achieved success as a pre-emergence weed control chemical for soybeans and other crops. As expected, soybean growth was reduced when the beans were grown in a nutrient solution containing small quantities of various substituted benzoic acids (Sutherland et nl., 1960). The greenhouse data in this report compare the plant growth inhibition produced by foliar application of TIBA with the inhibition caused by other halogenated benzoic acids. The desired result is maximum growth inhibition at low dosage rates and minimum phytotoxicity. TIBA meets this requirement better than any other chemical tested. MATERIALS AND METHODS
International Minerals & Chemical Corp., Growth Sciences Center, Libertyville, Ill. 2 Boyce Thompson Institute for Plant Research, Yonkers, N. Y . 1
976 J. AGR. FOOD CHEM.
Synthesis (at International Minerals and Chemical Corp., Libertyville, Ill,). Chemical intermediates were purchased from supply houses such as the Aldrich Chemical Co. or
Eastman Kodak and used as is. Melting points are uncorrected. Analyses were made by Micro-Tech Laboratories, Skokie, Ill., or by L. Ferrara and his associates a t International Minerals and Chemical Corp., Libertyville, Ill. 3,~-DIIODO-2-FORhlAMIDOBENZOIC ACID(NO. 18). Acetic anhydride (50 ml.) and formic acid (25 ml.) were combined in a 3-necked 500-ml. flask (Huffman, 1958). This solution was cooled and 3,5-diiodoanthranilic acid (50 grams, 0.125 mole) and 100 ml. of ether were added. The mixture was stirred for 20 hours a t room temperature. The product was filtered from the mixture and reslurried several times with ether. The yield was 47 grams (88%), m.p. 195196.5" C. Analysis Calcd. for C g H j I y N 0 3 :N, 3.34. Found: N, 3.16. ~,~-~IIODO-~-~ET~tOXYBE ACID N Z O I(NO. C 22). 2,3,5Triiodobenzoic acid (50 grams, 0.1 mole) was added to a freshly prepared solution of sodium methoxide (7.5 grams of Na, 0.35 gram atom) in 700 ml. of methanol. The solution was refluxed overnight, poured into 2 liters of water, and acidified with hydrochloric acid. The product was filtered from the cooled mixture; yield 40 grams ( ~ 1 0 0 % ) . Recrystallization from methanol gave 35 grams of product sintering at 200" C., m.p. 204-5" C. Analysis by gas chromatography demonstrated 99.9+% purity. AnalysisCalcd. for CsH61?Oa:C , 23.8; H, 1.50; I, 62.73. Found: C , 24.3; H, 1.52; I, 62.73. 2-CHLORO-5-IODOBESZOIC ACID(NO. 23). A SOhtiOn Of sodium nitrite (27.9 grams, 0.42 mole) in 150 ml. of sulfuric acid was added slowly, at 0" to 5" C., to a solution of 5iodoanthranilic acid (99 grams, 0.375 mole). The solution was stirred a n additional hour and poured over 4.5 kg. of ice. The solution was filtered and divided into three equal parts. Sodium chloride (150 grams) was added to one portion of the solution, followed by a solution of cuprous chloride (13 grams, 0.13 equivalent) in 75 ml. of concentrated hydrochloric acid. The mixture was heated o n the steam bath for 2 hours to complete the decomposition of the diazonium salt. The precipitate was filtered from the cooled solution, washed with water, and recrystallized from dilute ethanol. The yield of product melting a t 155.5-6" C. was 16.5 grams (47%). Analysis Calcd. for C;HICIIOy: C , 29.76; H, 1.43. F o u n d : C, 29.77; H ? 1.64. 3,~-DIBROMO-2-FOKMAMIDOBENZOIC ACID(NO. 27). USing the above formylation procedure, 3,5-dibromoanthranilic acid (27 grams, 0.092 mole) was allowed to react with 100 ml. of acetic anhydride and 50 ml. of formic acid. The product was recrystallized from acetone; yield 12 grams (41%), m.p. 185-7" C. Analysis Calcd. for CsH5Br?N03:N , 4.78. Found: N, 4.59. 3,5-DICHLORO-2-FORUAMIDOBENZOIC ACID (NO. 28). Using the above lormylation procedure, 3,5-dichloroanthranilic acid (43.2 grams, 0.21 mole) was allowed to react with 100 ml. of acetic anhydride and 50 ml. of formic acid. The product was recrystallized from acetone; yield 14 grams (2973, m.p. 240" C. Analysis Calcd. for CSHjC1,N03: N, 6.00. Found: N , 5.99.
n-DECYL-2,3,5-TRIlODOBENZOATE(NO. 36). 2,3,5-Triiodobenzoyl chloride (50 grams, 0.1 mole) (Klemme et ul., 1940) was dissolved in 150 ml. of benzene and 500 ml. of 1-decanol. The solution was allowed to stand a t room temperature overnight, then refluxed o n the steam bath for 2 hours, The volatile material was removed by distillation at reduced pressure. The product was recrystallized twice from acetone; yield 55 grams (88z),m.p. 38-40" C. An analytical sample recrystallized from methanol had m.p. 42-2.5" C. Analysis Calcd. for CIiHP3I3O2:C , 31.9; H, 3.60; I, 59.5. Found: C, 31.8; H , 3.59; I, 58.7. N-METHYL-2,3,5-TRIIODOBENZAMIDE (NO. 38). A SOlUtion of 2,3,5-triiodobenzoyl chloride (25 grams, 0.125 mole) in 100 ml. of tetrahydrofuran was added slowly to a cold 500-ml. solution of 4 0 z methylamine in water. Stirring was continued for 3 hours. The product was filtered from the mixture and recrystallized from acetone. The yield was 42.5 grams of material melting a t 235-43" C. The product was recrystallized twice from tetrahydrofuran-ethyl acetate; yield 30 grams (49 %), m.p. 243-5" C. Analysis Calcd. for CaH61aNO:N, 2.8. Found: N , 2.7. N,N-DIMETHYL-2,3,5-TRIIODOBENZAMIDE (NO. 39). USing the above procedure, 2,3,5-triiodobenzoyl chloride (176 grams, 0.34 mole) was allowed to react with dimethylamine (600 ml. of 25% aqueous solution). The product was filtered from the mixture and recrystallized from hot water; yield 134 grams (73%), m.p. 125-7" C. Analysis Calcd. for CgH81aNO: N, 2.66. Found: N, 2.70. 2,3,5-TRlIODOBENZOIC-2' , 2 '-DIMETHYLHYDRAZIDE (NO. 40). The above procedure, using 2,3,5-triiodobenzoyl chloride (51.8 grams, 0.1 mole) and dimethylhydrazine (13.5 grams, 0.2 mole) gave 34 grams (63%) of crude product. Recrystallization from ethanol yielded 18 grams (33%), m.p. 197.5-8" C. Analysis Calcd. for CgH91sNs0:C, 19.95; H, 1.67; I, 70.30; N, 5.17. F o u n d : C, 20.10; H , 1.68; I, 70.05; N , 4.83. ~,~,~-~RIIODO-~-(~'-HYDROXYETHYL)BENZAMIDE (NO. 41). Methyl 2,3,5-triiodobenzoate (50 grams, 0.0975 mole) was added to 300 ml. (excess) of ethanolamine. A thick slurry was formed which turned into a clear solution within half a n hour. The solution was stirred overnight. The product was isolated by pouring the ethanolamine solution into -2.5 liters of water. The precipitate was allowed t o stand for several hours before filtration. The yield of air-dried material was 54 grams (-equal to theoretical). The melting point, after three recrystallizations from ethanol, was 207-Y0 C. The infrared absorption spectrum of this compound, A,, 1640 cm.-l, is characteristic of amides. Analysis Calcd. for CgH81sNOn:C , 19.91; H, 1.49; I, 70.13; N , 2.58. F o u n d : C, 19.89; H , 1.50; I, 70.60; N , 2.47. ~,~,~-~RIIODO-~-(~'-AMINOETHYL)BENZAMIDE (NO. 42). Methyl 2,3,5-triiodobenzoate (50 grams, 0.097 mole) was added to 300 ml. of ethylenediamine with stirring. The solution was stirred for hour, poured into 1 liter of water, and the product filtered from the solution. The yield of crude material was 50 grams (92%). Recrystal-
VOL. 15, NO. 6, N0V.-DEC. 1967 977
Table I.
Phytotoxicity and Growth-Regulating Effects of Substituted Benzoic Acids
COOH 1
6
-
'
5
3 4
Compound No.
Control, maleic hydrazide
Source of Reference
-
Substituent (Other Than H)
L
4
3
5
6
Phytotoxicity Rating" and Other Effects* Rate, Pinto P.P.M. Tomato bean 5000 1000 500
BUY
100 20 Three halogens 1 (TIBA)
2 3
Buy
I
I
I
BUY Goldberg et al. ( 1946)
I
I
4
Buy
I
2"
5 6
Buy Weintraub et al. (1952)
I Br
NHCOCHi I
Weintraub et al. (1952)
c1
Weintraub et al. (1952) Weintraub et al. (1952)
I
c1
c1
Br
Br
Br
7
8
9
10 11
12
13
Buy Weintraub et al. (1952) Weintraub et al. (1952) Weintraub et al. (1952)
Br Br I
c1
I
I
I
I
I
I
2"
I
Br
c1
Br Cl
Br
Br
c1
c1
3
2
2 1 1
2bi Ir lr 1
1
5000 1000 500 100 20 5000 1000 5000 1000 500 100 20 5000 1000
2s 1s Is 1s
5OOo
1 3s, e 2s, e Is, e Is, se 4se Is, se Is, e Is, se
5000 1000 500 100 5000 1000 500 100 5000 1000 5000 1000 500 100 5000 5000 1000 5000 1000 500 100 5000 1000 500 100
1s Is
lsf 5
1 1 1
1 1 1
If
If 5 le, s, IC Is, e, IC Is, e, IC 1
4s 3s, r Is, r Is, r lr 3s 1s 3 1 1 1 1 2 2 1 4 2bi, IC, f 2s. bi, r: IC If, r, bi 4 lbi, f Is, r, bi Is, r 5
If 2f, IC If
Is, r Is, r 1
Growth Inhibition RatingC Pinto Tomato bean 4 4
2 1 1
4
4 3 2 2
3 3 3
4 4
2
3 3 3
.. 1 1
.. 1 1
1 1
2 1 1 5
3 3 3 5 4 3 3
4
1 4
1 4 2 1 2 2 1 .. 5 5 4 ..
5 4
3
..
1
.. 4 5
2 2 2 1
4 4 3 1
1
5
5
..
..
If
If, bi
2
5 Is, e, IC Is, e, IC Is, e
2sp, bi, f If, r,!bi If, r If 5 Ir, SP, f Ir, SP lf, r
..
4 5
5
1s If If
2 2
1
4 4 3
..
..
2 1
4 4 3
1
Two halogens 14
15 16
17 18 19 20
978
Wheeler and Johns (1910) Wheeler and Liddle (1908) Buy Buy New Knoefel et al. (1961) BUY
J. AGR. FOOD CHEM.
I
I
5000
1000 I I I NHCHO NHCOCHs
1
I
NH2
I I I
5000 1000 5000 1000
5OOo 5OOo 5000 lo00
OH
I
I
5000 1000
1 1 5 1 1 1 1 1
1 1 5 1
2 2 3 1 3 1 1 1 1 If 1 1
1 1
4
1
1 3 1 1 1 3
.. 1
1 1 1 1 1
.. 1
3 3
1
1 1
Table I.
Continued
21 22
BLI~ New
OCH,
23
New
CI
I
21
Bu!
Br
Br
25 26
BLI) Rosanoff and Prager (1908) New New Wheeler and Oates (1910) Buy New
27 28
29 30 31
One halogen 32 33
Bu!
OH
NHr
Br Br
Br Br
5000 5000 1000 5000 1000 5000 1000 5000 5000
NHCHO NHCHO NHCOCH,
Br CI Br
Br CI Br
OH NHCOCHa
Br CI
Br CI
I I
NHy
I
NHI
BLIJ Buq
31
I I
CI
NH?
CI
1 If
1
4 1 5
1
If If Is If 1 1
5000 5000 5000
1 1
1 1
1
1
5000 5000 1000
1
1
1
5000 1000
..
1
3
..
1
1 1 1 1 1
2s
5 2s, e 1 1
1 3 1
3
.. 3 1 1
1
1
1 1
1 2
1 1
1 1 1
1 2 3
1 1
4
1
..
1
1
1
5000
1
2
1000
1 1
2 1
1 1
1 1
1
1
5000
1
Ph) totoxicit) rating 1 = no iiijur) or normal stand -7 = slight iniur) or slight reduction in stand 3 = moderate injury or moderate reduction in stand 4 = severe injur) or severe reduction in stand 5 = all plants killed or n o stand Formatibe effects bi = bud inhibition s = severe e = rplnast> se = severe epinasty f = formati\c. sf = slight formatitr IC = leaf curl sl = strap leaf r = rosette s p = stem proliferatio!i Grou th inhibition rating 1 = equal to the control 2 = slight to 1 inhibition of gro\vth 3 = I . to > inhibition of growth 4 = to 1 inhibition of growth 5 = to complete inhibition of gro\vth '1
1
Table 11. Phytotoxicity and Growth Regulating Effects of TIBA Derivatives. COR
I I
Compound Source
NO.
35
OCH3
36 37
New Thompson et nl. (1946)
OCIOH23(/1)
38
New
NHCH3
39 40
New New
41 42 11
Marth and Mitchell (1 964)
R
New New
NHY
NHCHzCHzOH NHCHzCHzNH?
I
Rate, P.P.M.
Phytotoxicity Rating and Other Effects Pinto Tomato bean
Growth Inhibition Rating Pinto Tomato bean
5000
2s, se
2f, se
5
5
1000 500 100 5000 5000
2s, e 2s, e Is, e 1 1
2f, bi 2f, bi If, bi 1 If
5 4
5 4 4 1 3
3 1 1
1000
1
5000 1000
1
1
5000
1
5000 1000 5000 5000
If
If 1
1
1 2f 2f 1 1
1
4 4 1 1
1 3 1 1 4
3 1 1
Sce Table I footnotes.
VOL. 15, NO. 6, N0V.-DEC. 1967 979
Table 111. Response of Pinto Bean and Soybean to Substituted Benzoic Acidsa Phytotoxicity Rating and Other Effects Pinto Rate, P.P.M. bean SOJbean Compound No. Benzoic Acids 1000 2 2bi Control (maleic hydrazide) ... -7 2 500 1 1 100 20 1 1 4 1 1 7 1000 2s. r 1 (TIBA) 2,3,5-I 500 -7 Zf
-
2,4,6-1 3-NHz-2,4,6-1 2-Br, 3,5-I
100 20 4
1 1 1
500 100 20 500 1000
1 1 1
500 100
2-CI, 3,s-I
1000 500
100 8
2-1, 3,5-CI
20 500
100 20 9
11
2,3,5-Br
2-Br, 3,5-CI
4 1000 500 100 20 500 100 20
4 12
1.7
2-1, 3 5 B r
2.3,5-Cl
1000 500 100 20
1000 500
100 18
2-NHCHO, 3,5-I
19
2-NHCOCH3, 3,5-I
20 500
100 1000 500 100
24
29 35
36
2,5-Br
2-NHCOCH3, 3,5-Br 1-COOCH3,2,3,5-I (an ester)
1-COOCloH23(n), 2,3,5-I (an ester)
20 500 100 20 1000
1000 500
100 20 500 100
a
1
-7 -7
-7
lr 3
-7
Ir lr
-77 -
2 If 3
-7
Ir
Ir 2 2 1 If
-77 2 1 1
1
-7 1 1 I
-7 1 1 1 2 2 1 1
2 1
Ir 1
-7 1 1 1 3bi 2f 1 1 2
2s. r If. se If 3bi 2sl 1 1 2r
lr If 1 SI
Zf, SI Zf, SI 1SI lsl 1 1
2 1 1 1
4 If 1 1
2f, r 2f, r If, r 1 2 1
-
3
-7
3 1
1 1
5
5
4
4
3
1
3
1 3 3
1
4 2 1 1 5 5 1 5 4
-7
3
1 1 5 4 1 4 1 3
5
5
-7
3
-77 -
-7
3
3
2 2 5 4 3 3 5 3
3
2
5 4
5
3 3 5 4 3 2 I 1 3
3 3 5
1 1 1
2 1 1
2 2 1 1 4 4
, .
3 3
3 3
5 4
3 3 5
3
7
1
-7
4
1 3 2 2 1 * 7
2 1 1 3 4 2 1
See Table I footnotes
lization from methanol yielded 35 grams of product, m.p. 186-8" C. Analysis Calcd. for C,HsI,jN20:C, 19.95; H, 1.67; N, 5.17. Found: C, 19.74; H, 1.63; N, 5.10. Biological Evaluations (at Boyce Thompson Institute, Yonkers, N. Y . ) . Pinto bean (Phaseolus culgarisvar. Pinto.), 980
-7 -7 -7
If 1 1 1 1 1 1 2
Growth Inhibition Rating Pinto bean Soybean 5 5 4 4
J. AGR. FOOD CHEM.
soybean (GIycine n7a.x var. Lee), and tomato (Ljmperisicum esculenrum var. Bonny Best) plants were grown in 4-inch clay pots. When the Pinto bean and soybean plants had their primary leaves nearly fully expanded and the tomatoes were 4 to 5 inches high, a pot containing one or more plants of each test species was treated by placing o n a
revolving turntable in a hood and spraying with 100 ml. of the desired concentration of the test chemical. Each chemical was formulated with 100 p.p.m. of Triton X-100 (McCallan, 1948). A small amount of the chemical reached the soil in the pots. The plants were then maintained in the greenhouse for approximately 4 weeks, a t the end of which time the plant growth responses obtained were recorded. A code for plant effects is given a t the end of Table I. Phytotoxicity and growth inhibition data for substituted benzoic acids applied to Pinto bean and tomato are recorded in Table I. This table has three sections which list trihalogenated. dihalogenated, and monohalogenated benzoic acids in order. Table I1 lists results for derivatives of TIBA and Table I11 shows comparative results with Pinto bean and soybean. Some variation in test results with the same chemical will be noted in comparing Tables I and 111: since these were separate experiments. Some of the 2,3,5-trihalogenated compounds approach TIBA in effectiveness. However, Table I11 shows that undesirable phytotoxicity is greater and growth inhibition is less with compounds such as 2-chloro-3,5-dibromobenzoic acid (No. 7) or 2-iodo-?,5-dibromobenzoic acid (No. 12). ACKNOWLEDGMEST
The authors thank G. L. James for excellent technical assistance.
Anderson, I. C. (to Iowa State University Research Foundation), U. S. Patent 3,325,274 (June 13, 1967). Army, T. J., Soybeati Dig.26 (7), 24 (1966). Beatty, R. H. (to Amchem Products), Can. Patent 714,489 (July 27, 1965). Cathey, H. M., Atin. Rec. Plunt Pliysiol. 15, 271-302 (1964a). Cathey, H. M., Furm Chem. 127 ( I ) , 29-32 (1964b). Coombe, B. G.. Nature 205, 305-6 (1965). Crossan, D. F., Fieldhouse, D. J., Plrtit Disease Reptr. 48, 549-50 (1964). Goldberg, A. A,, Jefferies, H. S., Turner. H. S., Besly, D. M., Quart. J . Pliurm. undP/zunnueol. 19,483-90 ( I 946). Greer, H. A. L., Anderson, I. C.. Crop Sci. 5,229-32 (1965). Huffman, C. W.: J . Org. Chem. 23, 727-9 (1958). Keitt, G. W.. Jr., Baker, R. A.. Plrriit Pliysiol. 41, 1561-9 (1966). Klemme, C. J., Hunter, J. H.. J . Org. Cliem. 5,508 (1940). Knoefel, P. K., Huang, K. C . . Jarboe, C . H.. J . Pl~~rtnaeol. Exptl. Tlierup. 134, 266-72 (1961). Marth, P. C., Mitchell, J. W.; J. AGR. FOODCHEW12, 61-4 (1964). McCallan, S. E. A., Cotitrib. Boyce Thonipsoti ltist. 15, 71 (1948). Rosanoff. M. A,?Prager, W. L., J . Am. Cliem. SOC.30, 1903-4 (1908). Stebbins, B., Goocifr~ritGrower, p. 14 (May 1, 1965). Sutherland. M. L.. McLane. S. R.. Hart. R. D.. Ramen. H. L.. Proc. Northeust Weed Cotitrol Coif. 14, 31-9 (1960). Tahori, A. S., Zeidler, G., Halevy, A. H.. J . Sei. Food Agr. 16, 568-72 ... - 11962)
ThornpsoniH-E.. Swanson, C. P.. Norman, A. G., Botnti. Guz. 107,476-507 (1946). Tukey, L. D., Am. Fruit Grower 85 (May 1965). Weintraub, R. L., Brown, J. W., Nickerson, J. C., Taylor, K. N., Botun. Guz. 113,348-62 (1952). Wheeler, A. S., Oates, A. M., J . Am. Cliem. Soe. 32, 773 (1910). Wheeler, H. L., Johns, C . D., Am. Chem. J . 43, 398-411 (1910). Wheeler, H. L., Liddle, L. M., Am. Cliem J . 42, 441-61 (1908).
LITERATURE CITED
Anderson. I. C. (to Ioua State University Research Foundation), Can. Patent 726.639 (Jan. 25, 1966).
Receiced for reuiew June 20, 1967. Accepted Airgrr~t22, 1967.
VOL. 15, NO. 6, N0V.-DEC. 1967 981
